Watermelon Sue!
The towns of Rosemary and Seaside are about 8-10 miles apart. If you want to be close to Rosemary, as you know Inlet Beach is a great place, but Seacrest Beach is another option -- it's a development on the other side of Rosemary with a 12,000 sq foot lagoon pool that kids absolutely love. Seacrest is right between Rosemary and the new development Alys Beach, which mostly has a coffee shop/magazine/bookstore open right now.
If you want to be close to Seaside, I would stay on the west side of Seagrove Beach. There are a few people on this board with homes that are walking distance to Seaside.
Beaches are looking great and all walkovers are open, as far as I have heard! You should have no problems wherever you stay. If you think you might be interested in staying at Seacrest, we have a 3BR/3BA home with outstanding, unobstructed Gulf views from two floors. Send me a private message if you are interested!
Good luck with your search. This is the right place to come for the best info!